Introducers are designed to perform as a guiding sheath and / or introducer sheath , and can be ordered with a Tuohy-Borst valve or a Check-Flo'valve. Some introducers are available with a radiopaque band / tip incorporated within the sheath material to identify the location of the sheaths distal tip. Some introducers are also available with AQ " hydrophilic coating to provide a lubricious surface to ease insertion.